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Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Seven Sisters: 03-31 (14), 04-01 (13), 04-02 (11), 04-03 (9), 04-04 (7) — by astronomy; check the weather when the night is within four days.
2046-03-31astronomy score per night — click a bar for that night2046-04-29
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2046-03-31 Sat 14 — unknown 21:25–21:45 (good, 0.33 h) 72.6° 16:35 8.13 25% 108.8°
2046-04-01 Sun 13 — unknown 21:25–21:40 (good, 0.25 h) 72.6° 16:30 8.07 18% 96.9°
2046-04-02 Mon 11 — unknown 21:25–21:35 (good, 0.17 h) 72.6° 16:25 8.02 11% 85.1°
2046-04-03 Tue 9 — unknown 21:25–21:35 (good, 0.17 h) 72.6° 16:20 7.96 6% 73.3°
2046-04-04 Wed 7 — unknown 20:55–21:55 (marginal, 1.0 h) 72.6° 16:20 7.91 2% 61.5°
2046-04-05 Thu 6 — unknown 21:30–21:55 (marginal, 0.42 h) 72.6° 16:15 7.85 0% 49.5°
2046-04-06 Fri 5 — unknown 21:30–21:50 (marginal, 0.33 h) 72.6° 16:10 7.8 0% 37.5°
2046-04-07 Sat 4 — unknown 21:00–21:15 (marginal, 0.25 h) 72.6° 16:05 7.74 2% 25.4°
2046-04-08 Sun 3 — unknown 21:00–21:10 (marginal, 0.17 h) 72.6° 16:00 7.68 6% 13.0°
2046-04-09 Mon 2 — unknown 21:00–21:05 (marginal, 0.08 h) 72.6° 16:00 7.63 11% 0.8°
2046-04-10 Tue 1 — unknown — 72.6° 15:55 7.57 18% 12.2°
2046-04-11 Wed 1 — unknown — 72.6° 15:50 7.51 27% 25.1°
2046-04-12 Thu 1 — unknown — 72.6° 15:45 7.46 37% 38.2°
2046-04-13 Fri 0 — unknown — 72.6° 15:45 7.4 48% 51.7°
2046-04-14 Sat 0 — unknown — 72.6° 15:40 7.34 59% 65.5°
2046-04-15 Sun 0 — unknown — 72.6° 15:35 7.28 70% 79.7°
2046-04-16 Mon 0 — unknown — 72.6° 15:30 7.23 80% 94.2°
2046-04-17 Tue 0 — unknown — 72.6° 15:25 7.17 88% 108.9°
2046-04-18 Wed 0 — unknown — 72.6° 15:25 7.11 95% 123.8°
2046-04-19 Thu 0 — unknown — 72.6° 15:20 7.05 99% 138.8°
2046-04-20 Fri 0 — unknown — 72.6° 15:15 6.99 100% 153.6°
2046-04-21 Sat 0 — unknown — 72.6° 15:10 6.94 98% 168.2°
2046-04-22 Sun 0 — unknown — 72.6° 15:05 6.88 94% 177.4°
2046-04-23 Mon 0 — unknown — 72.6° 15:05 6.82 87% 163.7°
2046-04-24 Tue 0 — unknown — 72.6° 15:00 6.76 79% 150.3°
2046-04-25 Wed 0 — unknown — 72.6° 14:55 6.7 70% 137.3°
2046-04-26 Thu 0 — unknown — 72.6° 14:50 6.64 60% 124.7°
2046-04-27 Fri 0 — unknown — 72.6° 14:50 6.59 50% 112.5°
2046-04-28 Sat 0 — unknown — 72.6° 14:45 6.53 41% 100.4°
2046-04-29 Sun 0 — unknown — 72.6° 14:40 6.47 32% 88.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-03-31&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.